Using temperature as observable of the frequency response of RF CMOS amplifiers

The power dissipated by the devices of an integrated circuit can be considered a signature of the circuit's performance. Without disturbing the circuit operation, this power consumption can be monitored by temperature measurements on the silicon surface. In this paper, the frequency response of a RF LNA is observed by measuring spectral components of the sensed temperature. Results prove that temperature can be used to debug and observe figures of merit of analog blocks in a RFIC. Experimental measurements have been done in a 0.25 mum CMOS process. Laser probing techniques have been used as temperature sensors; specifically, a thermoreflectometer and a Michaelson interferometer.Peer ReviewedPostprint (author's final draft

Using temperature as observable of the frequency response of RF CMOS amplifiers

The power dissipated by the devices of an integrated circuit can be considered a signature of the circuit's performance. Without disturbing the circuit operation, this power consumption can be monitored by temperature measurements on the silicon surface. In this paper, the frequency response of a RF LNA is observed by measuring spectral components of the sensed temperature. Results prove that temperature can be used to debug and observe figures of merit of analog blocks in a RFIC. Experimental measurements have been done in a 0.25 mum CMOS process. Laser probing techniques have been used as temperature sensors; specifically, a thermoreflectometer and a Michaelson interferometer

Magneto-optical studies of iron impurity in HVPE GaN

24th International Conference on Defects in Semiconductors, Albuquerque, NM, JUL 22-27, 2007International audienceWe report on optical studies of bulk GaN crystals doped with iron. High-quality freestanding GaN crystals with varying Fermi level position were grown using the hydride vapor phase epitaxy on bulk GaN substrates. Samples with the dominant neutral Fe3+(3d(5)) acceptor state showed a characteristic near-infrared luminescence band around 1.3 eV, consisting of several sharp lines due to the fine structure of the T-4(1)(G)-(6)A(1)(S) internal transitions of isolated Fe3+ (d(5)) ions. In a magnetic field, these lines split into several components. This allowed us to determine energy structure of the T-4(1), multiplet in the magnetic field. For samples containing a singly ionized Fe2+(3d(6)) acceptor, absorption due to well-resolved E-5-T-5(2) internal transitions of Fe2+ was observed. Measurements performed at different temperatures ranging from 7 to 50 K and at magnetic fields up to 13 T enabled us to analyze some sublevels of the E-5 ground and the T-5(2) excited state. (C) 2007 Elsevier B.V. All rights reserved